Tempted by the fad diet that promises 15 or even 30 pounds of weight loss in the first month? While it would be lovely if excess weight could safely melt away, quick weight loss is unlikely, and prolonged extreme weight loss is not safe.

Weight Loss: Understanding That First Drop

"We usually recommend about a half a pound to two pounds a week, which is a lot less than what these fad diets promise," says Emily Banes, RD, clinical dietitian at the Houston Northwest Medical Center.

Banes acknowledges that some people may experience quick weight loss in the early stages of a new diet, but says it is important to be realistic about what to expect over the long haul. "If you have a lot to lose and you start on a diet and lose more than two pounds a week, that's not necessarily a bad thing, but know it's going to slow down," warns Banes, adding that some of the initial weight loss probably is water weight.

Even Banes' patients who have had lap-band or gastric bypass surgery and lose weight dramatically at first will eventually slow down to what feels like a crawl, but is actually a healthy rate of weight loss. Banes says she would worry about a person's rate of weight loss if they continued to lose five to 10 pounds (or more) a week.

Weight Loss: Safe Strategies, Best Strategies

While not everyone, including Banes, focuses on counting calories, doing the math can help guide you to a safer weight loss. Generally, experts recommend trimming 500 to 1,000 calories from your daily intake by eating less and exercising more.

A pound is the equivalent of 3,500 calories, so if you can cut 500 calories each day for a week, you should lose one pound. Researchers who analyzed data from 1,801 Minnesota dieters over a two-year period found that the more strategies dieters used, the more likely they were to be successful in losing weight at this pace. Strategies that lead to success include:

Counting calories
Increasing daily exercise (aim for 150 minutes a week or more)
Cutting out sweets and snacks
Reducing fat intake to less than 30 percent
Increasing fruit and vegetables
Decreasing portion sizes
The researchers noted that one crucial piece of information lacking from many diet strategies: persistence. Their conclusions support the fact that even though it will take a long time at the pound-per-week pace — longer than many people would like — with a slower approach you are more likely to develop the long-term healthy habits that will help keep the lost weight off.

Weight Loss: When the Rate Becomes Dangerous

If extreme weight loss means you are not getting enough nutrients — the fats, carbohydrates, and proteins needed for your body to function properly — you have entered the territory of unsafe weight loss. You may also be developing an eating disorder focused on your obsession with weight. Some of the warning signs that you may be losing too much weight are:

Thinning hair
Frequently becoming sick
Feeling cold more often than usual
Having fewer or no menstrual cycles
Disappointing though it may be, the reality is that slow and steady wins the weight-loss race. Take it easy and be patient — you will achieve your goal and, more importantly, maintain it.